US2128045A - Control system - Google Patents

Description

Aug. 23, 1938. Q R HANNA 2,128,045

CONTROL SYSTEM Filed Feb. 5, 1937 3 Sheets-Sheet 1 69:2. E F 38 72 W M? 5 :1.

fig. 38 V///////////// ATTO EY Aug. 23, 1938. c. R. HANNA 2,128,045

CONTROL SYSTEM Filed Feb. 5, 1937 3 Sheets-Sheet 2 INVENTOR ATT EY Patented Aug. 23, 1938 PATENT OFFICE con'mor. srs'mn Clinton R. Hanna, Pittsburgh, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh. Pa., a corporation of Pennsylvania Application February 5, 1937, Serial No. 124,258

12 Claims.

My invention relates to control systems for electric elevators, and more particularly to control systems for low speed or moderate speed elevators.

One object of my invention is to provide a control system which will automatically decelerate and stop a car exactly at a predetermined time after retardation is started and to so control that deceleration stop that that total time will be shorter than in previous systems and the stop will be effected more quickly and accurately; that is, to secure an ideal rate of slowdown and at the same time retain a high degree of accuracy in stopping. This is desirable because, in previous systems with which I am acquainted, accuracy in stopping has been sacrificed for a uniform and desirable rate of deceleration and slowdown of the car or good deceleration and slowdown has been sacrificed for accuracy in stopping level with the floor.

Another object of my invention is to provide a control system which will automatically control the rates of acceleration and deceleration of the car to secure the most desirable operation of the car.

A further object is to provide for maintainin a uniform rate of retardation of. the car when it is being decelerated from its normal running speed to a stop at a floor regardless of load and other conditions of operation.

Another object of my invention is to provide a control system in which the elevator car may be stopped accurately level with the floor at which a stop is to be made.

' For a better understanding of the invention 4 reference may be had to the accompanying drawings, in which:

Figure 1 is a diagrammatic illustration of an elevator system embodying my invention;

Fig. 2 is an enlarged view, in end elevation, of the deceleration controller mounted on the outer end of the shaft of the hoisting drum in the system shown in Fig. 1;

Fig. 3 is an enlarged view in cross-section, taken on the line III-III of Fig. 2, illustrating the interior construction of the controller;

Fig. 4 is an enlarged-view in cross-section taken along the line IV-IV of Fig. 2 and illustrating the interior construction of the controller at right angles to that shown in Fig. 3;

Fig. 5 is a view in cross-section taken on the line VV of Fig. 3 for the purpose of illustrating the inertia governor embodied in my invention; a

Fig. 6 is a view taken on the line v1- vI r Fig. 3 illustrating the contact rings and brushes on the controller for electrically connecting it to the control system illustrated in Fig. 1; Fig. '7 is a view, taken on the line VII--VII of Fig. 3, illustrating the centrifugal governor embodied in the controller illustrated in Fig. 1;

Fig. 8 is a diagrammatic representation of the electrical circuits for the elevator system illus-- trated in Fig. 1, these circuits being drawn in what is known as the straight line style; and

Fig. 8A is a representation of the relays embodied in Fig. 8 with their coils and contact members disposed in horizontal alignment with their positions in the straight-line circuits of Fig. 8, so that the reader may readily determine the identity of any relay, the number and kind of its contact members, and the position of its coil and its contact members in the straight-line circuits. The relays are named as follows:

U=up direction relay. D=down direction relay. P=intermediate speed time delay relay. Q=high speed time delay relay. E=high speed decelerating inductor relay. F=intermediate speed decelerating inductor reef lay. I V

G=relay for holding. inductor relay circuits. M=inductor restoring relay. UR=up stopping relay. DR=down stopping relay. K=interlocking control relay.

Hzcentrlfugal switch. S=inertia switch. T=deceleration control relay.

Referring more particularly to the drawings, I have illustrated an elevator system comprising a car C disposed in an elevator hatchway HA by a cable in passing over a hoisting drum II to a suitable counterweight l2. The hoisting drum is mounted on a shaft l3 rotatably supported in a plurality of bearings l4 and operated by a hoisting motor l5. An electromagnetic brake i6 is provided for controlling the speed of the motor and the hoisting drum. 7

The hoisting drum may be operated by any suitable motor, the one here illustrated being a three-phase alternating-current motor provided with primary windings 20, 2| and 22 and secondary windings 23, 24 and 25.

.The motor may be connected for operation to a. source of electrical energy by a supply circuit represented by the conductors Ll, L2 and L3. These conductors-may also provide energy to a control circuit for the motor represented by the conductors L+ and L- through a plurality of copper oxide rectifiers 28.

A car switch CS is mountedin the car for operation by a car attendant in starting and stopping the car. Die car switch is moved in a clockwise direction to start the car downwardly in a counter-clockwise direction to start the car upwardly; and to the center position to stop the car at the next floor.

An up direction relay U and a down direction relay D are controlled by the operation of the car switch for connecting and disconnecting the motor to its source of electrical energy in operating the car in either the up or the down direction.

An intermediate speed time delay relay P and a'highspeed time delay relay Q are provided for controlling the speed of the motor I! through connecting and disconnecting a plurality of resistors H to 1'6, inclusive, in response to the operation of the direction relays U and D.

In the system shown, the centering of the car switch causes the car to decelerate and stop only at the floors because the elevator is provided with an automatic stopping means which is effective onlyfor the floors; that is, the car switch may be centered for a stop any time after passing a floor until within a predetermined distance of the floor at which a stop is to be made and then the automatic stopping means will take up the operation at a predetermined point and cause the car to decelerate and stop exactly at the floor.

Any suitable automatic stopping means may be employed. As an example, I have illustrated an automatic inductor landing system similar to that disclosed in the White and Hearn Patent No. 1,884,446, issued October 25, 1932, and assigned to the Westinghouse Electric Elevator Company.

The inductor landing system includes a highspeed decelerating inductor relay E for initiating deceleration of the car while it is running at high speed, a second decelerating inductor relay F for causing the car to be automatically decelerated from its intermediate speed down to its stopping speed, and an up stopping relay UR and a down stopping relay DR. for bringing the car to rest alter it has been decelerated to stoppins p The decelerating inductor relay E ismounted on the car in position to cooperate with an inductor plate UE for the up direction and an inductor plate DE for the down direction. The intermediate relay F is mounted on the car in position to cooperate with an inductor plate UF for the up direction and aninductor plate DF for the down direction. The inductor plates are mounted in the hatchway in position to be passed by the relays on the car as the car moves up and down the hatchway. A set of inductor plates is provided for each floor.

As shown, each inductor relay is provided with two sets of contact members which are so connected with the car control circuits that, when the inductor relays are energized by. centering the car switch to effect deceleration and stopping of the car in the up direction, the contact members El as they pass the next up inductor plate UE are opened to decelerate the car, and as the contact members El come opposite the next inductor plate UF, they are openedto further control the deceleration of the car and deenergize the stopping relay UR. The deenergized relay U8 is provided with time delay means whereby it operates to stop the car level with the floor a' predetermined time after the relay F operates.

The down direction contact members on the inductor relays and the down direction stopping relay DR operate in the same manner for the down direction.

A locking relay G is provided for maintaining the inductor relay in their energized condition during the decelerating and stopping operation. An inductor restoring relay M is provided for releasing the inductor relays 'irom the control of the locking relay G and to prevent the inductor relays from being again energized until the car is moving and a new stop is to be made.

An interlocking control relay K is provided for energizing the inductor relay subsequent and in response to operation of the inductor relay E in passing its cooperating plate and for controlling certain other features in. connection with the deceleration of the car.

In prior elevator installations of the type 11- lustrated with which the applicant is acquainted, the ideal rate of deceleration of the car has been sacrificed for accuracy in stopping it level with the floor, or accuracy in stopping has been sacrideed for the sake of good deceleration and slowdown tothe stopping point. Therefore, I have provided means for so controlling the deceleration and stopping of an elevator car that its operation will be as smooth and rapid as possible for the speed for which it is designed and at the same time its accuracy in stopping level with the floor will be improved.

In practicing my invention, I have provided a control means including a deceleration controller I! mounted upon the outer end of the shaft ll of the hoisting drum li, a deceleration control relay T and connections with the control circuit for so controlling the coil 3| of the brake Ii as to effect the desired deceleration and stopping of the car.

The controller 30 includes an inertia switch S and a centrifugal switch H and is disposed to rotate with the shaft i3 upon which it is mounted. The controller is mounted on the shaft I3 by means of a stub shaft 32 (Figs. 3 and 4), the right end of which has a central projection 33 which extends into an aperture 34 (Fig. 4) in the shaft for the purpose of providing a firm connection therewith. A circular base plate 3 is mounted upon the outer end of the stub shaft 32.

A pair of screw bolts 3T-pass through the plate I and the stub shaft and into the end of the shaft II for the purpose of holding the plate and the stub shaft firmly in position on the shaft so that they wili rotate therewith. A cylinder 3| is mounted on the base plate and is retained in position thereon by a face plate 39. The face plate is constructed of insulating material and is held in position by a plurality of screw bolts .13 so that the base plate, the cylinder and the face plate constitute a casing for the controller.

The inertia switch S is mounted in the controller II and comprises a heavy bar l4 and two pairs of cooperating contact members l and 46. ,The bar is rotatably mounted, by means of ball bearings ll on a stubshaft or axle 42 extending through the base plate from the stub shaft. A plurality of screws 43 hold the bearings and the bar in correct position on the shaft. One of the contact members 45 is mounted upon one end of the bar II by means of a screw threaded stud II which passes through the bar and is insulated therefrom by an insulatingsleeve IS. A nut 5| is disposed on the screw threaded stud II in position tofasten the contact member 45 firmly,

on the bar M. The other contact member I! is 45 and 46 are so controlled by the contact members U1 and D1 that the contact members are effective only for the up direction and the contact members 46 for the down direction operation of the car.

The control system is also providedwith a deceleration control relay T associated with thecar control system in such manner as to control the connection through the slip-ring 98 during the operation of the controller 30. The contact members K2 of the relay K are also connected in the control circuit for the brake coil ill in such a manner as to assist in controlling the deceleration of the car.

It is believed that the invention may be best understood by an assumed operation of the apparatus herein described. It will be assumed that the system is designed for operating the car at a normal speed ofapproximately 320 feet per minute, and that the first stage of deceleration of the car when making an intended stop will bring it down from 320 feet per minute to approximately 60 feet per minute, that the second stage of deceleration will bring the car down approximately to rest. It will also be assumed that the inertia switch S is set to close at a predetermined rate of deceleration of, say 5 feet per second per second.

It will also be assumed that the contact members 84 of the centrifugal switch H are adjusted to open when the car exceeds a speed of 60 feet per minute and close when the car operates below 60 feet per minute.

In preparing the system for operation, the switches I are closed for connecting the motor circuit to the supply conductors LI, L2 and L3 and energizing the control supply conductors L+ and L-. The energization of conductors L+ and L- energizes the up direction stopping relay UR and the down direction stopping relay DR to close their contact members URI and DRI, to prepare the system for operation in either the up or the down direction.

Assuming that the car is standing at a door and that the attendant thereon operates the car switch CS in a counter-clockwise direction to cause the car to move upwardly, the operation of the switch closes its contact members III] and III, thereby energizing the up direction relay U and the inductor restoring relay M, the circuit extending from the supply conductor L+ through the car switch, III), III, URI, D3, U, M, XX, to L-.

The energization of the relay U closes its contact members UI, U2, U3, U5, U6, U1 and opens its contact members U4. The closing of the contact members UI and U2 and MI connect the windings of the motor I to the supply conductors LI, L2 and L3. The closing of the contact members U3 provide a self-h0lding circuit for the up direction switch which causes it to remain in operation until the automatic inductor relay stopping means operates to effect the stopping of the car.

The closing of the contact members U6 of the energized relay U and the contacts M3 of the energized relay M releases the brake It by energizing the brake coll 3| through a circuit extending from the supply conductor L+ through TI, I04, 98, 84, 96, I02, M3, 3| and US, to L. The brake is now released and the car starts on its trip.

The closing of the contact members U5 energizes the intermediate speed relay P which closes its contact members PI and P2 with a time delay and thereby short circuits the resistors r4, r5 and 16 in the secondary windings of the motor I5. This causes the motor to increase its speed. The energized relay P also closes its contact members P3, thereby energizing the high-speed relay Q to close its contact members QI and Q2, also with a time delay, thus short circuiting the resistors rI, T2 and r3 in the secondary windings 0f the motor I5 and causing the motor to now operate the car at its normal high speed.

The car is now operating upwardly at normal high speed and it will be assumed that the car' attendant decides to stop the car at the next floor. To do this he centers the car switch CS to render effective the automatic decelerating and stopping means for stopping the car level with the next floor. The centering of the car switch closes its contact members Ill! and I I2 and thereby energizes the decelerating inductor relay E and the inductor maintaining relay G. The energized relay G closesits contact members GI and thereby maintains the inductor relay system in operation until the stopping of the car is completed.

The inductor relay E is now energized and as the car continues its upward movement it approaches the up inductor plate UE for the floor at which the stop is to be made. As the energized relay comes opposite the plate, it is operated to open its contact members E I thereby deenergizing the relays, the interlocking relay K and the speed relays P and Q.

The deenergized speed relays open their contact members PI. and P2 and QI and Q2 at once and thereby reinsert the resistors TI to 1'6 in the secondary windings of the motor I5, thus reducing the speed of the hoisting motor to decelerate the car.

The opening of the contact members KI brings into operation my improved decelerating means by opening the main circuit I I4 for the brake coil and thereby throwing into effect the parallel or auxiliary circuits for the brake coil, one of which extends through the resistor 11, another oi which extends through the contact members of the inertia switch S, and another of which extends through the contact members of the centrifugal switch H. Inasmuch as the car at the start of its deceleration is not being retarded, the inertia switch contact members are open. and inasmuch as the car is operating at a speed above 60 ieet per minute, the contact members 84 of the centrifugal switch H are open. Therefore, the circuit for the brake coil 3| extends through the resistor r1 which partially deenergizes the brake coil to par tially apply the brake l6 so that the brake now assists in decelerating the car.

Assuming that the deceleration is at a rate greater than the desired predetermined rate for which the inertia switch S is adjusted, that excessive deceleration causes the inertia switch by reason of the inertia of the bar 44, to close its contact members 45 and thereby short circuit the resistor r1. The circuit for the brake coil now extends from the supply conductor L+, through contact members U'I, brush I03, slip ring 91, com tact members 45, slip ring 96, brush I02, contact members M3, brake coil 3|, and contact members US to supply conductor L. This applies Iull voltage to the brake coil and causes it to release the brake some and thereby decrease the rate of deceleration of the car.

The net effect is to cause a rapid change of voltage across the brake coil which because of the inductance of the coil and the inertia of the moving partsof the brake results in a braking torque just suflicient to maintain the desired rate of retardation of the elevator.

Assuming that during this first stage of deceleration the car decelerates to a speed slightly below 60 feet'per minute, then the centrifugal switch H closes its contact members 84 and thereby energizes the brake coil 3| by a circuit extending from the supply conductor L+ through Tl, I04, 98, 84, 96, 12, M3, 3| and US to L. The energized brake coil releases the brake completely so that the car increases its speed to slightly above 60 feet per minute under the action of the motor. This increase of speed now causes the contact members of switch- H to open and reduce-the voltage applied to the brake coil. The net effect here is to produce a brake torque just suiilcient to,

maintain a speed of 60 feet per minute. This speed is maintained for a short distance of car travel until further retardation takes place as will be described. The purpose of this short travel at reduced speed is to make up for discrepancies in the high speed from which the retardation started. These discrepancies are caused by variations in load, etc., that affect the full speed of the motor.

It will thus be seen that the car upon passing the first inductor plate after the centering of the car switch, will be decelerated from its normal high speed down to approximately 60 feet per minute, and that this deceleration will be controlled to within a desired predetermined rate by the operationof the inertia switch S and the centrifugal switch H.

Although the inertia switch has been described as opening and closing in a manner which would seem to occur every now and then, it will in actual practice open and close so fast and so often in controlling the deceleration of the car as to almost amount to continuous vibration. In fact if sired rate of deceleration. However, in the majority of cases, better results will be obtained if the resistor H is retained. Regardless of whether the action of the switches is slow or fast, the net result, as shown by operation, is that they operate in the manner described to control the deceleration of the car-within the predetermined limits within which the switches are adjusted to operate.

Assuming now that the car has decelerated to a speed of 60 feet per minute and that it has ap proached within such a distance 01' the next floor stop that the inductor relay F comes opposite the up inductor plate UF, and is thereby operated to open its contact members Fl.

The opening of the contact members Fl deenergizes the'up stopping relay UR to effect the stopping at a predetermined time thereafter. The opening of the contact members Fl also deenergizes the coil UT of the deceleration control relay T and, inasmuch as its coil ET is now unopposed by the coil UT, the relay T is energized to open its contact members H in the circuit through the centrifugal switch H. This renders the centrifugal switch H inoperative to aflect the further operation of the car while it is retarding from the 60 foot per minute speed, and the car will be further deceierated to approximately zero speed, through the control of the inertia switch 8.

Assuming now that the car in its further movement toward the floor at which it is to stop decelerates too rapidly, then the switch 8 is op-' erated by the inertia of the bar 44 to close its contact members 45 and thereby short circuit the resistor rl, thus fully energizing the brake coil :1

bers, again reinserting the resistor r! in the brake coil, cutting down the energization of the brake coil and causing it to only partially apply the brake IE to slow down the car. Assuming that the car slows down too rapidly, the bar 44 is again moved by its inertia and the rotation of the controller to close its contact members 45 and again short circuit the resistor r! to again fully energize the brake coil and thus fully release the brake It so that the car again speeds up.

The tendency of the elevator system is to cause the 'car to decelerate somewhat more rapidly than the predetermined desirable rate. Therefore the inertia switch S will keep short circuiting the resistor r'l every little bit to decrease the rate of deceleration of the car in opposition to its rapid rate of deceleration, and thus cause it to decelerate at the desired rate. As stated ,above, it is found in practice that the inertia switch S operates so often and so rapidly in decelerating the car that it is in almost constant vibration and practically brings the car down to rest at a practically constant rate of deceleration. And, as stated before, if it is desired to change the rate of deceleration that may be done by changing the position of the adjusting screws 63 and (Fig. 5).

The relay UR, as described above, is a timedelay relay. The relay is designed to have such until a predetermined time after it is deenergized. A fraction of a second only will be required for the car to change its speed from 60 feet per minute as it passes the second inductor plate until it comes approximately to rest. The time and the rate of deceleration being predetermined, the car will arrive at a point, say 2 inches from the 110 r at the speed of 5 feet per minute. At this poin the time-delay relay UR operates to open its contact members URI and thereby deenergiaes the up direction relay U and the inductor restoring relay M. The deenergized relay U opens its contact members Ul and U2 and the relay M opens its contact members Ml, thereby deenergizing the motor l5, causing it to stop the car. The opening of the contact members U6 deenergizes the brake coil 3!, and thereby causes the brake iii to be fully applied to stop and hold the car level with the floor at which the stop is being made.

The deenergized relay M opens its contact members M2 and thereby deenergizes the inductor relay group G, E and F, so that the stopping inductor relays will not be operated until the car is again in motion and'the car switch CS is again centered for another stop. The deenergization of the relay F closes its contactmembers Fl and thereby reenergizes the relay UR and the coil UT. Inasmuch as the coil ,UT opposes the coil DT, the deceleration control relay is again restored to its deenergized condition and this closes its contact members TI to restore the circuit to be controlled by the centrifugal switch that I have provided a system of control in which the car starts deceleration at a predetermined distance from afloor while operating at normal high speed, that this deceleration brings the car down to a speed of approximately feet per minute at the time it comes opposite the second inductor plate at another predetermined distance from the stopping floor, that it decelerates the car at a desired rate of deceleration from approximately 80 feet per minute at the second inductor plate to approximately zero speed when at the floor level, and that the car is then held level with the floor. 7

It will alsobe apparent from the foregoing description that the distance during which decelerv ation takes place is predetermined, that the rate of deceleration is predetermined and, therefore, that the car can be decelerated and stopped automatically level with the floor regardless of load or other conditions of operation. It will also be apparent that accuracy in stopping at the floor need not be sacrificed for the sake of securing a good rate of deceleration and, on the other hand, that a good rate of deceleration need not be sacriflced for the sake of securing accuracy in stopping level with the floor. a

It is tobe understood that the speeds, rates of deceleration, and distances referred to herein are given as examples but that other speeds.

rates of deceleration and distances may be utilized where desirable.

Although I have illustrated and described only one specific embodiment of the invention, it is obvious that many changes therein and modifications thereof may be made-without departing from its spirit and scope.

I claim as my invention:

1. In an elevator system for moving a car up or down to a floor, a hoisting motor for the .car, means for controlling the motor to operate the car, a brake for controlling deceleration and stopping of the car, a rotatable inertia switch,

. means for rotating the inertia switch in accordance with the speed of the car, and means responsive to a predetermined rate of deceleration in the rate of rotation of the inertia switch for decreasing the braking effect of the brake to decrease the rate of deceleration of the car.

2. In an elevator system for operating a car serving a floor landing, a hoisting motor for the car, a braking means, a swltching means, means responsive to one operation of the switching means for causing themotortostartthecarand responsive to another operation of the switching means for causing deceleration of the car to make a stop and for operating the braking means to retard the car, a decelerating control means including a centrifugal, device responsive to the speed of the car for reducing the braking eil'ect of the braking means when the speed of the car falls below a predetermined speed and an inertia deviw responsive to a predetermined car, a braking means; a switching means, means responsive to one operation of the switching means for causingthe motor tostart the car and cludingan inertia device and a centrifugal de- 5 vice, means for rotating the controller in accordance with the speed of the car, means responsive to operation of the inertia device at a predetermined rate of deceleration for decreasing the braking effect of the braking means to decrease 10 the rate of deceleration of' the car, means responsive to operation of the centrifugal device at a predetermined speed for reducing the braking effect of the braking means when the speed of the car falls below a predetermined speed, and means 5 responsive to operation of the switching means in operating the car for rendering the inertia device and the centrifugal device effective only during deceleration of the car.

4. In an elevator control system for a car servm ing a floor landing, a hoisting motor for the car, switching apparatus, means responsive to one operation of the switching apparatus for causing the motor to move the car upwardly responsive to another operation of the switching apparatus 25 for causing the motor to move the car downwardly and responsive to another operation of the switching apparatus for decelerating and stopping the car, braking means, means responsive to operation of the switching apparatus to a decelerate the car for applying the braking means to assist in decelerating the car, a decelcrating controller including a centrifugal device provided with a switch disposed to be operated by operation of the centrifugal device at a pre- 35 determined speed, an inertia device provided with an up" switch and a down switch disposed to be operated by'operation of the inertia device at a predetermined rate of deceleration,

means for rotating the controller in accordance 40 with the speed and direction of operation of the car, means responsive to operation of the switch on the centrifugal device'for reducing the braking effect of the braking means when the car falls below a predetermined speed, means re- 45 sponsive to operation of the up switch when the car is moving upwardly and responsive to operation of the down switch when the 'car is moving downwardly for decreasing the braking effect of the braking means to decrease the rate of decelm eration of the car, and means responsive to opvaeration of the switching means to decelerate the car 'for rendering effective the-switch on the centrifugal device and either the "up" or the down" switch .on the inertia device in accordance with 55 the direction of operation of the car only during deceleration of the car.

5. In an elevator system for operating a car serving a floor; motive means for the car, means for controlling the motive means to operate the on car, an electromagnetic brake for controlling the deceleration and stopping of the car, .a circuit for said electromagnetic brake, an inertia bar, a switch for each end of the inertia bar for connection in said circuit, means responsive to operation of the control means for up direction operation for connecting the switch on one end of theinertia bar for up operation in said circuit and responsive to operation of the control means for down direction operation for connect- 7 ing the switch on the other end of the inertia bar for down operation in said circuit, and means responsive to a predetermined rate of deceleration of the car for operating said inertia bar to close'the switch corresponding to the direction 1 2,198,045 of operation of the car to effect operation of theto another operation of the control means for decelerating the car to make a stop, an electromagnetic brake for assisting in decelerating and stopping the car, a main circuit for the brake. a' decelerating control means comprising an auxiliary circuit for the brake, means responsive to operation of the decelerating means for controlling saidmain circuit to effect application of the brake to retard the car, an inertia device responsive to a predetermined rate of deceleration of the car for reducing the braking effect of the brake to decrease the rateof deceleration of the car, a centrifugal switch responsive to a predetermined speed of the car for controlling said auxiliary circuit to reduce the braking effect of the brake when the car falls below said predetermined speed, and means responsive to operation of the car during its deceleration for rendering the inertia device and the centrifugal device effective for controlling the brake during a predetermined first stage of deceleration of the car.

'7 In an elevator system for operating a car serving a floor, motive means for the car, means for controlling the motive means to start and operation of the control means in'decelerating the car for rendering the decelerating control means effective .only during deceleration of the car. r

8. In an elevator system for operating a car serving a floor, motive means-for the car, control means for causing the motive means to start and to decelerate the car, an electromagnetic brake, a main circuit for the brake, a first auxiliary circuit and a second auxiliary circuit for controlling the brake, means responsive to operation of the control means to decelerate the car for rendering the main circuit ineffective and thereby effecting application of the brake to'decelerate the car and preparing the first and second auxiliary circuits for controlling the brake during deceleration, a centrifugal device responsive to opration'of the car at a predetermined speed during deceleration for controlling said first auxiliary circuit to reduce the braking effect of the brake when the car falls below said predetermined speed during deceleration, and an inertia device responsive to a predetermined rateof deceleration of the car for controlling said second auxiliary circuit to reduce the braking effect of the brake to decrease the rate of deceleration of the car. i

9; In an elevator system for operating a car serving a floo'r, motive means for the car, control means for causing the motive means to start and to decelerate the car, an electromagnetic brake. a main circuit, a first auxiliary circuit and a second auxiliary circuit and a resistor circuit for the brake, means responsive to operation of the control means to decelerate the car for rendering the main circuit ineffective and thereby effecting application of the brake in decelerating the car and for preparing thefirst and second auxiliary circuits for controlling the brake during deceleration, a centrifugal switch responsive to operation of the car at a predetermined speed during deceleration for closing the said first auxiliary circuit to reduce the braking effect of the brake when the car falls below said predetermined speed during deceleration and an inertia switch responsive to a predetermined rate of deceleration of the car for closing said second auxiliary circuit to reduce the braking eiIect of the brake to decrease the rate of deceleration .ofthe car, said remeans for causing the motive means to start and.

to decelerate the car, an electromagnetic brake,

(a main circuit and a first auxiliary circuit and a second auxiliary circuit for controlling the brake,

means responsive to operation of the control Y means-to decelerate the car for rendering the main circuit ineffective and thereby effecting application of the brake to assist in decelerating the-car and preparing the first and second auxiliary circuits for controlling the brake during deceleration, a centrifugal deviceresponsive to operation of the car at a predetermined speed during deceleration for controlling said first auxiliary circuit to reduce the braking effect oif the brake when the car falls below said predetermined speed during the first stages of deceleration, an inertia device responsive to a predetermined rate of deceleration of the car for controlling said second auxiliary circuit to reduce the braking eilfect of the-brake for decreasing the rate of deceleration of the car during the first and second stages of deceleration, and means responsive to operation of the control means for rendering the centrifugal device effective only during the first stage of deceleration and for rendaring the inertia device effective only during the first and second stages of deceleration.

11. In a controlsystem for an elevator car, motive means for the car, control means, means responsive to one operation of the control means for operating the motive means to start the car, decelerating means responsive to another operation of the control means and to the approach of the car to apredetermlned distance from the point at which a stop is to be made for initiating deceleration of the car for a stop, a brake for controlling deceleration of the car, an inertia switch responsive to a predetermined rate of deceleration of the car for controlling the brake to decrease the rate of deceleration when the car exceeds said predetermined rate of deceleration, a'centrifugal device responsive to a predetermined rate of speed of said car during one'stag'e of deceleration to reduce the braking eifect of the brake to decrease the rate of deceleration of the car when it falls below said speed during said stage of deceleration, means responsive to operation of the decelerating means for rendering the centrifugal device eflective only during the first stage of deceleration and for rendering the inertia device effective only during the first and second stages of deceleration, and a stopping device re sponsive to the approachot the car to a second predetermined distance from the point at which the stopis to be made for eflecting application 0! the brake a predetermined time thereaiter to stop the car, for decelerating the car at a predetermined rate and in a predetermined time from the point of initiation or deceleration to the relay for eflecting an increased speedof the motor, a high speed relay responsive to energizetion 0! the intermediate speed relay for electing a higher speed oi the motor. a decelerating relayv responsive to a stopping operation of the switch and to a predetermined position of the car for deenergizing the speed relays to cause deceleration oi the motor and the car, a brake, means responsive to operation oi the decelerating relay for applying the brake to decelerate the car, a decele'rating control means comprising an inertia device responsive to a predetermined rate of deceleration oi the car for releasing the brake to decrease the rate 0! deceleration, a centrifugal device responsive to a predetermined speed of the car ior'releasing the brake when the car 1 falls below said predetermined speed, a second decelerating relay responsive to operation or the first decelerating relay and a second predetermined position ot the car for rendering the centrifugal deviceineilective to control the brake during a second stage of deceleration of the car, and a stopping relay responsive to operation of said second decelerating relay and the expiration of a predetermined time thereafter for eilecting operation oi the brake to stop the car and for rendering the said decelerating control means ineii'ective to operate.

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